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[PATCH v2 2/2] x86: reimplement mem boot option

 

 

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wency at cn

Aug 21, 2012, 1:11 AM

Post #1 of 2 (75 views)
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[PATCH v2 2/2] x86: reimplement mem boot option

Current mem boot option only can work for non efi environment. If the user
specifies add_efi_memmap, it cannot work for efi environment. In
the efi environment, we call e820_add_region() to add the memory map. So
we can modify __e820_add_region() and the mem boot option can work for
efi environment.

Signed-off-by: Wen Congyang <wency [at] cn>
---
arch/x86/kernel/e820.c | 29 +++++++++++++++++++++++++----
1 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 4185797..20bc467 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -47,6 +47,7 @@ unsigned long pci_mem_start = 0xaeedbabe;
#ifdef CONFIG_PCI
EXPORT_SYMBOL(pci_mem_start);
#endif
+static u64 mem_limit = ~0ULL;

/*
* This function checks if any part of the range <start,end> is mapped
@@ -119,6 +120,20 @@ static void __init __e820_add_region(struct e820map *e820x, u64 start, u64 size,
return;
}

+ if (start >= mem_limit) {
+ printk(KERN_ERR "e820: ignoring [mem %#010llx-%#010llx]\n",
+ (unsigned long long)start,
+ (unsigned long long)(start + size - 1));
+ return;
+ }
+
+ if (mem_limit - start < size) {
+ printk(KERN_ERR "e820: ignoring [mem %#010llx-%#010llx]\n",
+ (unsigned long long)mem_limit,
+ (unsigned long long)(start + size - 1));
+ size = mem_limit - start;
+ }
+
e820x->map[x].addr = start;
e820x->map[x].size = size;
e820x->map[x].type = type;
@@ -809,7 +824,7 @@ static int userdef __initdata;
/* "mem=nopentium" disables the 4MB page tables. */
static int __init parse_memopt(char *p)
{
- u64 mem_size;
+ char *oldp;

if (!p)
return -EINVAL;
@@ -825,11 +840,11 @@ static int __init parse_memopt(char *p)
}

userdef = 1;
- mem_size = memparse(p, &p);
+ oldp = p;
+ mem_limit = memparse(p, &p);
/* don't remove all of memory when handling "mem={invalid}" param */
- if (mem_size == 0)
+ if (mem_limit == 0 || p == oldp)
return -EINVAL;
- e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);

return 0;
}
@@ -881,6 +896,12 @@ early_param("memmap", parse_memmap_opt);

void __init finish_e820_parsing(void)
{
+ if (mem_limit != ~0ULL) {
+ userdef = 1;
+ e820_remove_range(mem_limit, ULLONG_MAX - mem_limit,
+ E820_RAM, 1);
+ }
+
if (userdef) {
u32 nr = e820.nr_map;

--
1.7.1
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wency at cn

Sep 5, 2012, 2:28 AM

Post #2 of 2 (64 views)
Permalink
Re: [PATCH v2 2/2] x86: reimplement mem boot option [In reply to]

Hi, H. Peter Anvin

Do you have time to review this patch?

Thanks
Wen Congyang

At 08/21/2012 04:11 PM, Wen Congyang Wrote:
> Current mem boot option only can work for non efi environment. If the user
> specifies add_efi_memmap, it cannot work for efi environment. In
> the efi environment, we call e820_add_region() to add the memory map. So
> we can modify __e820_add_region() and the mem boot option can work for
> efi environment.
>
> Signed-off-by: Wen Congyang <wency [at] cn>
> ---
> arch/x86/kernel/e820.c | 29 +++++++++++++++++++++++++----
> 1 files changed, 25 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> index 4185797..20bc467 100644
> --- a/arch/x86/kernel/e820.c
> +++ b/arch/x86/kernel/e820.c
> @@ -47,6 +47,7 @@ unsigned long pci_mem_start = 0xaeedbabe;
> #ifdef CONFIG_PCI
> EXPORT_SYMBOL(pci_mem_start);
> #endif
> +static u64 mem_limit = ~0ULL;
>
> /*
> * This function checks if any part of the range <start,end> is mapped
> @@ -119,6 +120,20 @@ static void __init __e820_add_region(struct e820map *e820x, u64 start, u64 size,
> return;
> }
>
> + if (start >= mem_limit) {
> + printk(KERN_ERR "e820: ignoring [mem %#010llx-%#010llx]\n",
> + (unsigned long long)start,
> + (unsigned long long)(start + size - 1));
> + return;
> + }
> +
> + if (mem_limit - start < size) {
> + printk(KERN_ERR "e820: ignoring [mem %#010llx-%#010llx]\n",
> + (unsigned long long)mem_limit,
> + (unsigned long long)(start + size - 1));
> + size = mem_limit - start;
> + }
> +
> e820x->map[x].addr = start;
> e820x->map[x].size = size;
> e820x->map[x].type = type;
> @@ -809,7 +824,7 @@ static int userdef __initdata;
> /* "mem=nopentium" disables the 4MB page tables. */
> static int __init parse_memopt(char *p)
> {
> - u64 mem_size;
> + char *oldp;
>
> if (!p)
> return -EINVAL;
> @@ -825,11 +840,11 @@ static int __init parse_memopt(char *p)
> }
>
> userdef = 1;
> - mem_size = memparse(p, &p);
> + oldp = p;
> + mem_limit = memparse(p, &p);
> /* don't remove all of memory when handling "mem={invalid}" param */
> - if (mem_size == 0)
> + if (mem_limit == 0 || p == oldp)
> return -EINVAL;
> - e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);
>
> return 0;
> }
> @@ -881,6 +896,12 @@ early_param("memmap", parse_memmap_opt);
>
> void __init finish_e820_parsing(void)
> {
> + if (mem_limit != ~0ULL) {
> + userdef = 1;
> + e820_remove_range(mem_limit, ULLONG_MAX - mem_limit,
> + E820_RAM, 1);
> + }
> +
> if (userdef) {
> u32 nr = e820.nr_map;
>

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